1. Field of the Invention
The present invention relates generally to ink jet printing apparatus and more particularly to ink jet printing apparatus wherein the ink droplet producing portion of the apparatus is rotatable with respect to the print receiving media.
2. Description of the Prior Art
The most pertinent known prior art is U.S. Pat. No. 3,373,437 to R. G. Sweet, et al. entitled, Fluid Droplet Recorder with a Plurality of Jets, filed Aug. 1, 1967, issued Mar. 12, 1968. The apparatus described in the Sweet patent includes means for mounting a plurality of ink droplet jet producing nozzles for printing upon a cylindrically defined and supported record member. The Sweet apparatus uses rotatably mounted charge plates as well as rotatably mounted deflection plates. Operation of this configuration would require rotatably mounted high and medium voltage power supplies or the conduction of high and medium voltage signals across slip rings. These problems apparently have been sufficiently difficult to overcome that there is no known presently available rotary ink jet printing apparatus.
Continuous ink jet with variable charge voltage and constant deflection voltage is employed by many ink jet printers. The IBM 6640 and Mead Dijit represent two printers in this class. The IBM 6640 is well known for the high quality character printing produced while Mead Dijit is known for very fast printing of characters and graphics. A rotary binary ink jet would provide the best of both of these types of apparatus.